VPT 321: Veterinary Neuropharmacology (2+1)

BENEFICIAL EFFECTS AND TOXICITY

• Beneficial actions of NSAIDs
• As analgesic 
• Antipyretic and
• Antiinflammatory
• Anti thrombotic – NSAIDs inhibit both Proaggregatory Thromboxanes (TXA₂) and Antiaggregatory Prostacyclin (PGI₂) but effect on Thromboxanes predominate. Thus, increase bleeding time
• Closure of ductus arteriosus – Patency of Ductus in foetal life is maintained by local prostaglandins, and closes after birth. In case of a failure of closure of ductus, NSAIDs will help to close the ductus by inhibiting prostaglandins.

Clinical applications of NSAIDs

• Fever
• Analgesia
• Peripheral pain
• Musculoskeletal pain
• Endotoxaemia
• Anticoagulant (platelet) activity
• Patent ductus arteriosus closure
• As an adjunct therapy in mastitis with antibiotics in veterinary practice.

Toxicity

• Gastric Ulceration
  • Major toxicity of NSAIDs. prostaglandins exert cytoprotective effect by protecting the mucous membrane against attack by acid.
  • NSAIDs, by inhibiting prostaglandins lead to exposure of Mucosa to acid causing erosion, ulcers and bleeding
  • Typical ulcers are reported in dogs and horses
• Renal – Prostaglandins regulate local blood flow in kidney. With other nephrotoxic agents or conditions like shock, dehydration leading to  edema, Na⁺ retention, nephrosis
• Delay in labour process owing to inhibition of prostaglandins which have a role in parturition
• Hepatotoxicity – possible with all NSAIDs. Paracetamol forms a hepatotoxic metabolite by an alternate pathway (glucuronidation - poor in cats)
• Blood dyscriasis – phenylbutazone – causes blood dyscrasias
• Asthma and anaphylactic reactions in many individuals – due to overproduction of leukotrienes